A colleague and I would like to know how many patent families were started under certain CPC codes in recent years. In our understanding, patent families contain several applications for the same innovation, so we'd be interested in counting only the first application within each family. Secondary goals include very roughly evaluating the "quality" of patent families through the family size and family citations. We're quite new to this and don't require much more.
We have noticed sometimes very large discrepancies between what I downloaded last year (on the Spring 2015 version) and what he's obtained this year (on both Spring and Autumn 2015 versions).
Last year I carried out a very simple yearly patent family count of three different CPC codes on 2015 Spring version of PATSTAT:
Y02E 10/1 Geothermal energy
Y02E 10/4 Solar thermal energy
Y02C 10 Carbon capture and storage
None of them has had any changes (that we can see here: http://www.cooperativepatentclassificat ... anges.html)
Queries are very simple, like this:
Code: Select all
SELECT DISTINCT t.prior_earliest_year, t.nb_citing_docdb_fam, t.docdb_family_size, t.docdb_family_id FROM tls201_appln t JOIN tls224_appln_cpc cpc ON cpc.appln_id = t.appln_id WHERE cpc.cpc_class_symbol LIKE 'Y02C 10%'
Y02C 10 (CCS) shows minimal discrepancies for both Spring (just 8 patent families below total figure for 2005-2012 as downloaded last year) and Autumn versions (only 2 patent families below total figure but slightly larger differences each year)
Y02E 10/1 (Geothermal) shows far greater discrepancies. Spring 2015 data that I downloaded last year gave me a total patent family count of 1313 for 2005-2012. Spring 2015 data that we downloaded recently gave a total of 2417. Autumn 2015 data was 2401.
Y02E 10/4 (Solar thermal) shows similarly large discrepancies.
Would anyone have any clues as to what could be happening here? Any advice on what table/column to use for the year of earliest filing of an application within a given patent family?
Any help would be much appreciated!!